Mars and Twitter are in the clear following scrutiny from the advertising watchdog over a Snickers marketing campaign on the social networking site.

The regulator was called in after complainants challenged whether postings sent from the official accounts of footballer Rio Ferdinand and model Katie Price could be clearly identified as adverts.

In its first investigation involving Twitter, the Advertising Standards Authority (ASA) dismissed the objections and ruled the two series of tweets did not breach industry codes.

The online postings - which both related to Snickers - popped up on the micro-blogging site within an hour in January.

In his first tweet, Manchester United and England defender Ferdinand wrote: "Really getting into the knitting!!! Helps me relax after high-pressure world of the Premiership."

In further postings, he added: "Can't wait 2 get home from training and finish that cardigan"; "Just popping out 2 get more wool!!!"; "Cardy finished. Now 4 the matching mittens!!!"

A fifth read: "You're not you when you're hungry @snickersUk#hungry#spon ..." and included a picture of the player holding a Snickers bar.

Price's tweets followed a similar pattern.

The first read: "Great news about China's latest GDP figures!!"

It was followed by: "Chinese leaders are now likely to loosen monetary policy to stimulate growth. Yay!!"; "OMG!! Eurozone debt problems can only properly be solved by true fiscal union!!! #comeonguys"; and "Large scale quantitative easing in 2012 could distort liquidity of govt. bond market. #justsayin."

The final posting read: "You're not you when you're hungry @snickersUk #hungry #spon ..." and showed a picture of the mother-of-three holding a Snickers.

Mars told the ASA that in each case the fifth tweet stated "#spon" to indicate the content was "sponsored".

"They said the fifth tweets were the only ones that featured the product and were therefore the only marketing communications involved," the ASA said.

While the watchdog disagreed, insisting that each tweet formed part of an "orchestrated advertising campaign", it accepted Mars's use of Twitter.

"We noted the first four tweets in each series served as 'teasers', which, due to their nature, were likely to generate additional interest in the celebrities' postings," it said.

"We also noted those tweets did not make any reference to Snickers or to Mars and were posted in relatively quick succession.

"In addition, we noted that the fifth 'reveal' tweets showed the celebrities with the product and included the text "You're not you when you're hungry @snickersUk #hungry #spon ...".

"We considered the combination of those elements was sufficient to make clear the tweets were advertising and that consumers would then understand each series of tweets was a marketing communication."

The watchdog ruled it was "acceptable" that the first four tweets were not individually labelled as being part of the marketing campaign.